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    <title>Document</title>
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<body>
    <script>
        // includes() 判断数组当中是否有某一个值 返回布尔值
        let arr = ['a', 'b', 'c']
        let flag = arr.includes('b')
        let re = arr.includes('e')
        console.log(flag);//true
        console.log(re);//false

    </script>
</body>

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